412. _Epieikeia_ may be defined, therefore, as a moderation of the words of the law where in an extraordinary case, on account of their generality, they do not represent the mind of the lawgiver; which moderation must be made in the manner in which the lawgiver himself would have made it, had he thought of the case, or would make it now, were he consulted. Hence, _epieikeia_ differs from the various causes that take away the obligation of a law, for it supposes the non-existence of obligation from the beginning and non-comprehension in the law. Thus: (a) it is not revocation, desuetude, restrictive interpretation, or dispensation; (b) it is not cessation on account of impossibility; (c) it is not presumed permission or self-dispensation. 413. In its use _epieikeia_ is at once lawful and dangerous. (a) It is lawful, for it defends the common good, the judgment of conscience, the rights of individuals from subjection to a written document, and from oppression by the abuse of power; (b) it is dangerous, for it rests on the judgment of the individual, which is prone to decide in his own favor to the detriment of the common good as well as of self. 414. _Epieikeia_ by its very nature imposes certain limits on its use. (a) It is based on the fact that a certain case is not comprehended in a law, because the legislator did not foresee it. Hence, _epieikeia_ is not applicable to the Divine Law; for the Divine Lawgiver foresaw all cases that could arise, and so excluded all exceptions (see 315). This is clear as regards the Ten Commandments and other precepts of the Natural Law, since they deal with what is intrinsically good or bad, and are unchangeable (see 307). But it applies also to the prescriptions of the Positive Law of God, and apparent cases of _epieikeia_, such as the eating of the loaves of proposition by David (I Kings, xxi. 6), can be explained by the cessation of law or divine dispensation. Examples: One may not excuse certain modern forms of cheating on the plea that they were not thought of when the Decalogue was given. One may not omit Baptism on the ground that Christ Himself would have excused from it, had He foreseen the circumstances. (b) _Epieikeia_ is based on the principle that the words of a law must be subordinated to the common good and justice. Hence, it is not applicable to those laws whose universal observance is demanded by the common good--that is, to irritant laws. Any hardship suffered by an individual through the effect of such laws is small in comparison with the injury that would be done to the common welfare if there were any cases not comprehended in such laws; for irritant laws are the norms for judging the validity of contracts and other acts, and public; security demands that they be uniform and certain. Example: One may not contract marriage with a diriment impediment, on the plea that the Church would not wish the impediments to oblige under the serious inconvenience that exists in one’s case.